Blood Alcohol Concentration Values Research Articles

Verbal memory and executive components of recall in adolescent binge drinkers.

Binge drinking (BD) is a common health-risk behavior among young people. Due to the incomplete maturation of the adolescent brain, BD can lead to structural and functional changes that impact neurocognitive processes, particularly executive functioning and verbal memory. This study aimed to investigate the influence of executive components, such as mnemonic strategies and error avoidance, on performance in a verbal memory test and the potential effects of BD on this performance. A sample of 160 college students (51.55% female) with a mean age of 18.12 ± 0.32 years completed assessments for alcohol use disorders using the Alcohol Use Disorder Identification Test (AUDIT), as well as psychopathological (Symptom Checklist-90-R) and neuropsychological evaluations (Verbal Learning Test Spain-Complutense and WMS-III Logical Memory). The Intensive Drinking Evaluation Instrument (IECI) was utilized to gather detailed information about binge drinking habits, including the calculation of the highest blood alcohol concentration (BAC) during an episode of intake. Correlation and clustering analyses revealed a negative association between BAC values and verbal memory performance, as well as the use of memory strategies. The high BAC group (BD) exhibited negative values in verbal memory variables, higher accuracy errors, and less efficient strategy usage, while the low BAC group (No BD) demonstrated better memory test performance, fewer precision errors, and superior use of memory strategies. These findings support the hypothesis that, when solving tests requiring verbal memory, adolescents reporting a BD consumption pattern show fewer executive skills in their resolution and, therefore, achieved poorer performance than non-binge drinkers. Addressing excessive alcohol consumption in young individuals is crucial for safeguarding their cognitive development and overall well-being.

Comparisons ofBlood Alcohol Concentrations between Initial Testing andReanalysis from Unopened Tubes Preserved with 0.25% NaF Following Refrigerated Storage up to 3.93 Years.

Few studies support the usage of <1% nominal sodium fluoride (NaF) to preserve ethanol in antemortem blood. Of these studies, several are limited by short study durations of 90 days or less, and there is limited research of authentic samples preserved with <1% NaF. In this retrospective analysis, data from initial and reanalysis testing of blood alcohol concentration (BAC) in antemortem blood collected in 6 mL gray-top tubes (providing 0.25% nominal NaF) has been compiled, to evaluate changes in ethanol concentration that occurred after periods of refrigerated storage. The time between initial and reanalysis was determined by court request(s), and ranged 0.30-3.93 years. In each case, a previously unopened tube was selected for reanalysis testing. Comparable BAC values were found from initial testing, with BACs ranging from 0.025 to 0.394 g/100 mL, and reanalysis testing, with BACs ranging from 0.021 to 0.393 g/100 mL. Ethanol changes ranged from -0.013 g/100 mL (decrease) to 0.008 g/100 mL (increase). BAC reanalysis values that increased (n = 6) were within the uncertainty of measurement (UM) from the initial BAC test, i.e., were not statistically or analytically significant. For BAC decreases (n = 29), four test values exceeded the UM of the original test, with BAC losses ranging from 0.004 to 0.011 g/100 mL (relative percent changes 6.5-16.0% loss). The average ethanol change was -0.004 g/100 mL, which is comparable to or less than ethanol losses from studies using 1% NaF preservative of varying temperature and storage duration.

A Disposable and Noncontact Paper Breathalyzer Based on Small Conjugated Molecules/Carbon Nanotubes Electrodes

Herein, N,N′‐di(decyl)‐3,4,9,10‐perylenebis(dicarboximide) (PDIC10) is first functionalized by hydrothermal synthesis method and processed onto single‐walled carbon nanotube (SWCN) electrodes and paper substrate. The PDC10/SWCN/paper device can be applied as a noncontact breathalyzer to detect and quantify ethanol alcohol and determine equivalent blood alcohol concentration (BAC). The sensing mechanism increases the electrical resistance upon ethanol alcohol (EtOH) exposition. This device allows the quantification of BAC values from 0.01% to 0.2%, with ΔR (%) of 2–25% in this range, with adequate stability operating in cycles.

A ‘Hands on’ Public Service Program to Help People Stay Sober and Safer on the Roadway

Despite the existence of many different “Don’t drink and drive” programs and campaigns over the past 30 years, alcohol intoxication has continued to account for approximately one quarter to one third of all traffic crashes and crash-related deaths in the United States. The present study describes a new ‘hands on’ evidence-based approach involving real alcohol-intoxicated subjects using a virtual reality (VR) driving ‘game’ to educate the public more effectively about the dangers of drunk driving. A single demonstration subject ‘drove’ a VR-based portable driving simulator on multiple occasions before (Pre) and at 30 min intervals for up to six hours after either vehicle (no alcohol), two, four or six ‘drinks’ (3, 6, or 9 ounces of 80 proof vodka). The defensive driving task was a choice reaction crash avoidance steering maneuver in which the driver’s task was to determine which way to turn to avoid a crash and then aggressively steer away to avoid a crash. The primary dependent variable was the latency to initiate an avoidance steering response. Blood alcohol concentration (BAC) determinations (estimations) were conducted immediately prior to driving tests using BAC Track portable breathalyzers. Control drives (Pre-Treatment and Vehicle treatment) were characterized by an approximately 300–320 ms reaction time to initiate a crash avoidance. Alcohol increased crash-avoidance reaction time. Peak BAC values were 35, 78 and 120 mg/dL for two, four and six drinks, respectively; the decline in BAC was comparable and linear for all three treatments. There was a strong correlation (r = 0.85) between pre-drive BAC level and reaction time across all of the alcohol-related drives. There was a significant increase in crash avoidance reaction time when the BAC was 50–79 mg/dL, which is below the legally defined BAC limit (80 mg/dL) currently used in most states in the US. These results demonstrate that (1) this VR-based driving simulator task could be a useful ‘hands on’ tool for providing public service demonstrations regarding the hazards of drinking and driving and (2) a BAC concentration of 50 mg/dL represents a reasonable evidence-based cut-off for alcohol-impaired driving.

Statistical comparisons of blood alcohol samples from 6-mL and 10-mL grey-top tubes.

Historically, blood alcohol concentration (BAC) studies utilized a 1% concentration of the preservative sodium fluoride (NaF), leaving an information gap supporting usage of lower concentrations of NaF to preserve ethanol. As many forensic laboratories utilize Becton, Dickinson and Company 6-mL gray-top tubes (0.25% NaF), statistical comparisons were conducted to determine whether significant differences exist between BAC values obtained from 6-mL tubes versus 10-mL tubes (1% NaF). Whole blood was spiked at three concentrations, (0.04, 0.08, and 0.15g/100mL) and aliquoted into tubes at "low," "medium," and "high" fill volumes. Tubes were split into refrigerated or ambient storage and analyzed after 1, 3, 5, 7, and 30days, using headspace gas chromatography. Each 6-mL and 10-mL tube pair, prepared, stored, and analyzed under identical conditions, was compared by t-test (95% confidence level). For refrigerated tubes, 32 of 45-tube pairs did not reject the null hypothesis (that 6-mL and 10-mL tubes yield equivalent BACs), and 31 of 45 ambient stored tube pairs did not reject the null hypothesis. Analysis of variance (ANOVA) found no significant differences between 6-mL and 10-mL gray-top tubes for 0.04 and 0.15g/100mL concentrations over 30days; significant differences were observed for 0.08g/100mL concentration tubes, which warrants further study. Paired t-tests of grouped samples found no significant differences between 6-mL and 10-mL tubes at any concentration.

Significant decrease in the rate of fatal alcohol poisonings in Finland validated by blood alcohol concentration statistics

BackgroundAlcohol may cause death directly by acute poisoning, as well as induce illnesses or accidents that lead to death. Our research question was whether the current decreasing trend in acute fatal alcohol poisonings in Finland is a real phenomenon or an artefact caused by possible changes in the process of determining the cause of death. MethodsAll cases in the national post-mortem toxicology database in which the underlying cause of death was acute alcohol poisoning in 1987–2018 were investigated in terms of blood alcohol concentration (BAC), age and gender. The number of acute alcohol poisonings was compared to the number of deaths from alcohol induced illness in the post-mortem toxicology database. ResultsA total of 12 126 acute alcohol poisoning cases were retrieved. Between 2004 and 2017 the number of acute alcohol poisonings decreased 60.1 %. At the same time the number of alcohol induced illnesses in the study material remained stable or decreased marginally.The median BAC in all acute alcohol poisonings was 3.2 g/kg. The annual median BAC values showed a small but significant decrease over the study period. The proportion of women in acute alcohol poisonings increased significantly over the study period, from 17.1%–22.3%. Women were on average 2.5 years older than men. ConclusionsOn grounds of the BAC statistics and supporting evidence, we conclude that the significant decrease in the number of fatal alcohol poisonings is true and likely reflects changes in the overall consumption of alcohol.

Baseline breath alcohol concentration in Nigerian commercial drivers and motorcyclists

ABSTRACTObjective: We sought to determine breath alcohol concentration (BrAC) in a sample of consenting Nigerian commercial drivers and motorcyclists and relate values obtained to some social parameters and practices.Method: A cross-sectional study of randomly selected, consenting commercial drivers, and motorcyclists in two Nigerian cities was undertaken. We obtained data on subjects’ sociodemographics, driving/riding related experiences and practices with the aid of a pretested structured questionnaire. We determined their BrAC and analyzed data using SPSS version 17.0. Statistical significance was inferred at p ≤ 0.05.Result: One hundred ninety respondents aged 20–65 years mean (SD) 40 (11.28) were studied. They were 112 (58.9%) drivers, 78 (41.1%) motorcyclists, and predominantly males (98.9%). A significant proportion of motorcyclists were aged <40 years and most drivers >40 years (p < 0.001). Respondents’ educational attainment did not differ significantly with age groups and status; however, 6.8% had no formal education.Alcohol use decreased significantly with increasing years of experience (p < 0.001). Note that 68.9% of respondents tested positive with the breathalyzer with blood alcohol concentration (BAC) levels 0.01–1.8 mg/ml with mean (SD) at 0.16 (0.32) mg/ml. In total, 51.1% of respondents had BAC values ≥0.1% while 7.9% had BAC ≥0.5 mg/ml. A total of 92.6% admitted use of various measures to enhance their performances and overcome fatigue.Conclusion: The drink driving/riding law in Nigeria needs to be revised to suit prevailing circumstance and enforced.

الأهمية القانونية لقيم التراكيز الحدية للكحول في الدم عند قيادة المركبات في القانون الجنائي الألماني؛ دراسة مقارنة بالقانون الإماراتي والمصري

Driving under the influence of alcohol or drugs (DUI) is a crime or offence according to the laws of most countries. DUI increases the risk of traffic accidents as well as the severity and outcome of injuries that result from them. Some countries have a sophisticated control system to monitor DUI of alcohol in all traffic accidents. There is variation between different countries regarding the concept of driving under the influence of alcohol as well as the legal limits of Blood Alcohol Concentration (BAC) and the requirements to test the victims of accidents. This paper reviews the limit values for BAC in German traffic law (Administrative Offences Act), which stipulates a BAC value of 0.50 mg/g and a breath alcohol value of 0.25 mg/L as a marginal value for the application of punitive measures. German criminal law defines the minimum BAC values of relative unfitness to drive and absolute unfitness to drive as 0.3 mg/g and 1.10 mg/g, respectively (1.60 mg/g for cyclists).The minimum BAC values representing significant impairment and absolute impairment in criminal cases are 2.00 mg/g and 3.00 mg/g, respectively. Different penalties and legal consequences result according to the BAC level of an offender. In contrast, only eight out of twenty-two Arab countries recognise BAC limit values only in traffic laws. In Jordan, the BAC limit is 0.75 mg/g (0.08 g/dL).in the UAE, the BAC limit is 0.094 mg/g (0.01 g/dL), while Egyptian law does not recognise BAC values in the application of sanctions: the mere presence of alcohol in blood, regardless of its concentration and effect, is a sufficient and adequate condition for punishment. Accordingly, this study encourages lawmakers in Arab countries to define the limit values for BAC when investigating any crime in general and traffic offences in particular, in close cooperation with forensic doctors and toxicologists. It urges them to consider different BAC and their effects in relation to traffic offences. It also encourages them to take into account the principle of hierarchy in criminal liability when a crime is committed under the influence of alcohol.

Circadian Sleep Propensity and Alcohol Interaction at the Wheel.

The study was aimed at estimating the effect of alcohol consumption, time of day, and their interaction on traffic crashes in a real regional context. Blood alcohol concentration (BAC) data were collected from drivers involved in traffic accidents during one year in an Italian region and in a control group of drivers over the same road network. Mean circadian sleep propensity was estimated from a previous study as function of time of day. Accident risk was analyzed by logistic regression as function of BAC and circadian sleep propensity. BAC values greater than zero were found in 72.0% of the drivers involved in crashes and in 40.4% of the controls. Among the former 23.6% of the drivers exceeded the BAC legal threshold of 0.05 g/dL, while illegal values were found in 10.4% of the controls. The relative risk showed a significant increase with both BAC and circadian sleep propensity (as estimated from time of day) and their interaction was significant. Due to the significant interaction, even low BAC levels strongly increased accident risk when associated with high sleep propensity.

Driving under the influence of alcohol. A 5-year overview in Piedmont, Italy

Alcohol consumption represents a major health issue worldwide and a crucial factor in road accidences. This study provides information on the prevalence of alcohol in blood testing performed on 2752 subjects involved in vehicle accidents, which occurred in Piedmont (northern Italy) between 2008 and 2013. Blood alcohol concentration (BAC) was determined by an ISO 17025 accredited GC/MS procedure. Fifty-one % of positive samples showed BAC concentrations above 1.5 g/L, with a legal cut-off fixed at 0.5 g/L (and 0 g/L for specified categories such as novice and professional drivers). BAC values proved statistically different regarding the day of sampling (week or weekend days), age and gender, with a prevalence of positive results that reflects different drinking habits of a multifaceted population of alcohol consumers.

Alcohol-related emergency department admissions among adolescents in the Ghent and Sint-Niklaas areas

Alcohol abuse is a major health concern. The aim of this retrospective study was to analyse the alcohol-related emergency department (ED) admissions among adolescents in all hospitals of distinct areas during a 1-year period. In each hospital, all ED patients with a blood alcohol concentration (BAC) of at least 0.5 g/l were surveyed in a standardised way. Of the 3918 included patients, only 146 (3.7%) were < 18 years. The male-to-female ratio was 1.5:1. There was a strong preponderance of weekend and night time admissions. Most of the patients were transported by ambulance (77% of 138 patients with information on this item). The main reason for ED admittance was depressed level of consciousness (64%), trauma (12%), vomiting and/or abdominal pain (12%), agitation or aggression (4%), syncope (4%) and psychological problems (4%). The context of the alcohol intoxication was related to some kind of festivity in 85%, mental problems in 14% and chronic abuse in 1%. Median BAC values (and range) were 2.08 g/l (0.73–3.70 g/l) for boys and 1.51 g/l (0.73–2.90 g/l) for girls. Most patients (87%) could be discharged home within 24 hours. Our study confirms that problematic alcohol use leading to ED admissions starts in adolescence. Although the numbers of cases below 18 years are low when compared to adults, the phenomenon is alarming as it is associated with substantial health problems. Therefore, Belgium urgently needs a global national alcohol plan, with youngsters being one of the target groups.

Comparison of the Effects of Two Legal Blood Alcohol Limits: The Presence of Alcohol in Traffic Accidents According to Category of Driver in Izmir, Turkey

Objectives: Under existing Turkish road traffic law, there are 2 different blood alcohol concentration (BAC) limits allowed for drivers in 2013: zero blood alcohol and ≤0.50 g/L. All public transport, taxi, commercial, and official vehicle drivers must maintain a zero blood alcohol concentration while driving. Private vehicle drivers must maintain a BAC of 0.50 g/L or lower. The aim of the recent study was to evaluate the effect of these 2 legal blood alcohol limits on nonfatal traffic accidents that occurred due to the driver being under the influence of alcohol.Methods: This retrospective study was performed to evaluate the blood alcohol concentration of 224 drivers in nonfatal road accidents between June 2010 and July 2011 using headspace gas chromatography at the Izmir Forensic Medicine Group Presidency, Turkey. All cases evaluated by the toxicology department were entered into a database. We used descriptive statistics, χ2 test, and independent sampling test to analyze the data.Results: The total number of drivers involved in nonfatal traffic accidents was 224; 191 were private vehicle drivers and 33 were public transport, taxi, commercial, and official vehicle drivers. In the present study, alcohol was detected in the blood of about 27.2% (n = 61) of the 224 drivers. Sixty (31.4%) private vehicle drivers involved in nonfatal traffic accidents tested positive for alcohol. BAC values were also above the legal limit (0.50 g/L) in 27.7% (n = 53) of private vehicle drivers. However, the BAC was above the legal limit in only 3% (n = 1) of public transport, commercial, and official vehicle drivers involved in nonfatal traffic accidents. These results showed that private vehicle drivers subject to a BAC limit of ≤0.50 g/L were significantly associated with an increased risk of nonfatal accident involvement than drivers subject to a zero BAC limit (odds ratio [OR] = 12.29, 95% confidence interval [CI], 1.64–92.22; Fisher's exact test, P <.001). Mean BAC in private vehicle drivers subject to a 0.50 g/L level (52.60 mg/dl ± 94.84) was significantly higher than that of drivers subject to a zero alcohol level (10.76 mg/dl ± 61.80; t = 2.44, P <.001).Conclusion: In light of our results, lowering the BAC limit for private vehicle drivers may reduce the level of driving under the influence of alcohol. A change in the law will decrease the rates of alcohol-related road accidents in Turkey.

Breath Analyzer Screening of Emergency Department Patients Suspected of Alcohol Intoxication

BackgroundAcute alcohol intoxication is a frequent cause of emergency department (ED) visits. Evaluating a patient’s alcohol intoxication is commonly based on both a physical examination and determination of blood alcohol concentration (BAC). ObjectiveTo demonstrate the feasibility and usefulness of using a last-generation infrared breath analyzer as a non-invasive and rapid screening tool for alcohol intoxication in the ED. MethodsAdult patients suspected of acute alcohol intoxication were prospectively enrolled over 10 days. Breath alcohol concentrations (BrAC) were measured using a handheld infrared breath analyzer. BAC was determined simultaneously by automated enzymatic analysis of a venous blood sample. The relationship between BAC and BrAC values was examined by both linear regression and Bland-Altman analysis. ResultsThe study included 54 patients (mean age 40±14 years, sex ratio M/F of 3/1). Breath and blood alcohol concentrations ranged from 0 to 1.44mg/L and from 0 to 4.40g/L (0–440mg/dL), respectively. The mean individual BAC/BrAC ratio was 2615±387, 95% confidence interval 2509–2714, which is 30% higher than the legal ratio in France (2000). The correlation between both measurements was excellent: r=0.95 (0.92–0.97). Linear regression revealed BAC=0.026+1.29 (BrAC×2000) and BAC=0.026+0.99 (BrAC×2615). Mean BAC-BrAC differences and limits of agreement were 0.49 g/L [−0.35, 1.34] (or 49 mg/dL [−35, 134] and 0.01 g/L [−0.68, 0.71] (or 1 mg/dL [−68, 71]), for the 2000 and 2615 ratios, respectively. ConclusionThe calculated conversion coefficient provided a satisfactory determination of blood alcohol concentration. Breath alcohol testing, using appropriate BAC/BrAC conversion, different from the legal BAC/BrAC, could be a reliable alternative for routine screening and management of alcohol intoxication in the ED.

Do Objective Measures of Blood Alcohol Concentrations Make More Sense than Self-reports in Emergency Department Studies?

: Concerns about self-reports have led to calls for objective measures of blood alcohol concentration (BAC). The present study compared objective measures with self-reports. : BAC from breath or blood samples were obtained from 272 randomly sampled injured patients who were admitted to a Swiss emergency department (ED). Self-reports were compared a) between those providing and refusing a BAC test, and b) to estimated peak BAC (EPBAC) values based on BACs using the Widmark formula. : Those providing BACs were significantly (P < 0.05) younger, more often male, and less often reported alcohol consumption before injury, but consumed higher quantities when drinking. Eighty-eight percent of those with BAC measures gave consistent reports (positive or negative). Significantly more patients reported consumption with negative BAC measures (N = 29) than vice versa (N = 3). Duration of consumption and times between injury and BAC measurement predicted EPBAC better than did the objective BAC measure. : There is little evidence that patients who provide objective BAC measures deliberately conceal consumption. ED studies must rely on self-reports, eg, take the time period between injury and ED admission into account. Clearly, objective measures are of clinical relevance, eg, to provide optimal treatment in the ED. However, they may be less relevant to establishing effects in an epidemiologic sense, such as estimating risk relationships. In this respect, efforts to increase the validity and reliability of self-reports should be preferred over the collection of additional objective measures.

Deficits of respiratory-cardiac coupling in heavy drinkers

1. Physiological evidence of chronic alcohol abuse prior to the onset of clinical signs of alcohol dependence is difficult to obtain. The purpose of this study was to search for possible non-invasive indicators for chronic alcohol consumption yielding information in addition to conventional biological markers 2. The authors investigated the relationship between respiratory-cardiac coupling and blood alcohol concentration (BAC) in male subjects who lost their driver's license from drunk driving. 3. We found that subjects who had a high BAC level (0.16–0.31% at the time of offense) show altered respiratory sinus arrhythmia (RSA) and, in particular, an altered heart-rate response to auditory stimulation and compared them to a control group of social drinkers. Normal subjects showed a pronounced acoustic heart-rate response, i.e., particularly during expiration there was a difference between the interbeat-interval (IBI) traces with and without auditory stimulation. Subjects who had lost their driver's license from drunk driving had an overall severely reduced heart-rate response, that was even absent particularly in the subgroup having high BAC values (0.21–0.31%). The authors also found some evidence that in the latter subgroup IBI, RSA, and acoustic heart-rate responses partially recover after a six-month period of abstinence. 4. Specific parameters of the acoustic heart-rate response are changed in our group of alcohol abusers presumably, due to impairment of vagal function. These parameters may therefore be useful to serve as a non-invasive measure of alcohol abuse.

Monitoring Ethanol Exposure in a Clinical Setting by Analysis of Blood, Breath, Saliva, and Urine

Several new technologies have been developed for estimating blood alcohol concentration (BAC), among others, by the analysis of alcohol in saliva specimens. The Q.E.D. is a new quantitative test designed for measuring ethanol in saliva and promising results have been obtained in various experimental settings. In the present study, venous BAC was determined in 28 patients on arrival and when they were discharged from a detoxification unit. The results were compared with breath, saliva, and urine alcohol concentrations. Headspace gas chromatography was used for analysis of ethanol in blood and urine, and breath alcohol was determined with an Alcolmeter S-D2 instrument. The concentration of alcohol in urine was always higher than the BAC (mean difference, 0.62 mg/ml) and individual values were highly correlated (n=42; r=0.92). The handheld breath-alcohol instrument (Alcolmeter S-D2) showed good agreement with venous BAC (n=52; r=0.97; mean difference, 0.04 mg/ml). The saliva-alcohol test failed to perform well in our tests (n=36; r=0.75; mean difference, 0.55 mg/ml) mainly because of problems encountered in obtaining a sufficient sample for analysis in highly intoxicated patients. Because of the relatively low cost of the Q.E.D. ' saliva test, in comparison with a breath alcohol analyzer, the saliva test could be a cost-effective alternative in public health settings where mildly to moderately intoxicated persons are encountered.

The validity of police assessment of driver intoxication in motor vehicle crashes leading to hospitalisation

We evaluated the accuracy of the field sobriety assessment of police officers following a motor vehicle crash. Using linked data from a statewide traffic crash database and the trauma center registry, the results of a field sobriety evaluation for each driver were compared with a blood alcohol concentration (BAC) drawn in the emergency department. BAC values served as the “gold standard” in which drivers with values over 0.1mg/dl were classified as intoxicated. The subjects were drivers over age 15 years who were admitted or died at Level I trauma center as a results of motor vehicle crash injuries during 1986–1993. A total of 1336 subjects had both a recorded BAC and a police sobriety assessment. Seventy percent of subjects were male and 79% under the age of 35 years. Overall, 40% of all subjects were judged by police to have been impaired, based on the scene sobriety assessment. Among all drivers, the field assessment had a sensitivity of 91%, a specificity of 90% and a predictive value positive of 85%. After excluding the 419 drivers which had breath testing as part of their assessment, the field assessment had a sensitivity of 74% and a specificity of 97%. The sensitivity of the field assessment did not vary appreciably by gender but was lower among older drivers, and higher among severely injured drivers and those involved in weekend and nighttime crashes. Police officers in this sample appear to recognize drunk driving with a high degree of accuracy when investigating crashes in which the driver is transported to a trauma center.

Guidelines for estimating the amount of alcohol consumed from a single measurement of blood alcohol concentration: re-evaluation of Widmark's equation

This article deals with the pharmacokinetics of ethanol and the reliability of estimating the amount of alcohol ingested from a single measurement of a person's blood alcohol concentration (BAC). Blood alcohol curves were plotted for 108 male subjects after they drank various doses of ethanol (0.51–0.85 g/kg body weight). The rate of disappearance of ethanol from the blood (β-slope) and the apparent volume of distribution of ethanol (Widmark's rho factor, ϱ) were calculated for each subject; the mean β-slope was 13.3 mg/dl/h (SD = 2.0), and the mean ϱ factor was 0.689 l/kg (SD = 0.061). The value of β increased slightly with increasing dose of alcohol ( P < 0.05). The blood alcohol parameters β and ϱ were negatively correlated (r = −0.135). The BACs measured at 2 h and 5 h post-drinking were used to estimate the amount of alcohol each subject had consumed according to the method proposed by Widmark [1]. The mean differences (estimated-actual) and the ±95% limits of agreement were −0.72 g (± 12), and 2.2 (± 15), for the 2 h and 5 h BAC values, respectively. A method based on error propagation was used to derive the 95% limits of uncertainty in the amount of alcohol ingested. On the basis of a single measurement of BAC, we could estimate the amount of alcohol ingested within ±20%.

Blood alcohol concentrations of sudden unexpected deaths and non natural deaths

This study reports on the relationships between the blood alcohol concentration (BAC) and the cause of death — which is of course common knowledge for forensic scientists! Our special aim was to gain unselected data for generalizing conclusions. The blood of 2465 consecutive cases (86% of all 2852 sudden unexpected and unnatural fatalities investigated at the Institute for Legal Medicine in Hamburg during the year 1989) was analysed. The BAC was evaluated according to sex, age, cause of death and place of death. In natural causes of death there were 80% cases under 0.05‰ BAC. Endocrine and digestive system diseases in particular were associated with positive BAC values. In unnatural death cases the BAC under 0.05‰ was found in 6401. of the suicides, 62070 of the accidents, 54% of the homicides and 51% of the drug intoxications. The drowning cases showed higher BAC's than traffic accidents. In suicides middle aged males had high BAC's.

Accurate measurement of blood alcohol concentration with isothermal rebreathing.

The importance of interaction of exhaled air with the airway surface was evaluated by comparing the effects of different breathing maneuvers and inhaled air temperature on the relationship between breath alcohol concentration (BRAC) and blood alcohol concentration (BAC). Breath alcohol was measured with an infrared absorption unit. Blood and simulator liquid alcohol concentrations were measured by gas chromatography. Breath samples were measured after both low and high exhaled volumes and after rebreathing. Breathing maneuvers were performed after either hyperventilation, breathhold or normal breathing. Inspired air temperature was varied between 0 degree C and 40 degrees C. The rebreathing method for sampling alveolar alcohol samples was evaluated with a new isothermal rebreather that was designed to provide a substantial amount of heat to the rebreathed air in order to heat the airway surfaces. Using a single breath test, the indicated BAC values vary from 14% above the actual BAC to as low as 55% below the actual BAC. Hyperventilation caused a significant decrease in BRAC and breathhold caused a significant increase in BRAC. When isothermal rebreathing is applied to such tests, the breath test results were always within +/- 10% of the true BAC, even with an altered breathing pattern. Isothermal rebreathing provided an accurate sample of alveolar air that was not affected by altered breathing pattern or air temperature.